Senior citizens are emerging as a formidable obstacle to President Obama's ambitious health-care reform plans.

The discontent in the powerful and highly organized voting bloc has risen to such a level that the administration is scrambling to devise a strategy to woo the elderly.

Obama's task will not be easy. Proposals to squeeze more than $500 billion out of the growth of Medicare over the next decade have fueled fears that his effort to expand coverage to millions of younger, uninsured Americans will damage elder care. As a result, barely one-third of seniors support a health-care overhaul, several polls found.

"People have gotten more and more worried," said Nancy LeaMond, a vice president at the 50-and-over advocacy group AARP, which will unveil a pro-reform TV and print ad campaign Monday. "They are very concerned about the myths they keep hearing that care will be rationed and they won't have access to doctors."

One mailing from the 60 Plus Association, which bills itself as a "conservative alternative to AARP," warns that the proposed Medicare changes will mean "longer wait times at hospitals and doctors offices, less money for new treatments, restrictions on care, prescriptions and what's best for you -- the patient!" Officials at the Virginia-based group did not respond to several messages last week.

Conservative talk-radio shows have raised the prospect of euthanasia based on a provision to reimburse doctors through Medicare for counseling sessions about end-of-life directives.

And comments posted on former Alaska Republican governor Sarah Palin's Facebook page Friday said that people would have to "stand in front of Obama's 'death panel' so his bureaucrats can decide, based on a subjective judgment of their 'level of productivity in society,' whether they are worthy of health care."

There are no such "death panels" mentioned in any of the House bills.

From the raw numbers, it appears seniors are the net losers under bills approved by three House committees last week. The legislation trims $563 billion out of Medicare's growth rate over the next 10 years while pumping in about $320 billion. Without any changes, the program is expected to cost about $6.4 trillion over the same period.

But three retiree groups and several independent policy analysts say most of the proposed savings affect providers, rather than beneficiaries, and have the potential to improve quality over the long term. Discounts for prescription drugs, higher reimbursements for many doctors and elimination of co-payments for preventive services are some of the ideas advocates applauded.

"I don't see anything that will affect beneficiaries' access to care, though some of it will depend on implementation," said Joseph Baker, president of the Medicare Rights Center, a nonprofit group focused on older Americans.

Senior citizens have long had doubts about Obama. Voters 65 and older were the only age group to choose Sen. John McCain (R-Ariz.) in last year's presidential election, according to exit polling that looks at four common age groups. Those polls show McCain won seniors 53 percent to 45 percent.